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941.
针对旁路烟道旋转喷雾干燥技术和主烟道蒸发技术,开展了脱硫废水蒸发干燥过程及其产物特性的分析对比研究,比较了两种工艺过程中脱硫废水蒸发特性,并对脱硫废水蒸发产物的表面结构特性进行了研究,考察了Cl元素的迁移分布特性及其对后续除尘系统和粉煤灰资源化利用的影响。结果表明:氯离子浓度增大,蒸发效果会随之降低,pH值则对其影响不大,旋转雾化条件较之于主烟道蒸发效果好;两种工艺下蒸发干燥产物表面粗糙,烟道出口S元素含量增加明显,Ca、Mg、K等元素略有增加,蒸发后产物大致相同,由于温度的不同,旋转雾化条件主要是以莫来石、SiO_2、Al_2O_3、 KCl、MgSO_4、CaSO_4·0.5H_2O为主,主烟道蒸发则是以莫来石、SiO_2、Al_2O_3、KCl、MgSO_4·H_2O、CaSO_4·0.5H_2O和CaSO_4·2H_2O等为主;废水中氯离子浓度对氯元素以HCl形式进入烟气影响不大,而碱性脱硫废水则可以有效抑制其以HCl形式析出。 相似文献
942.
采用微波辅助加热法干法制备阳离子淀粉,详细考察了微波功率、微波辐照时间、氢氧化钠用量和3-氯-2-羟丙基三甲基氯化铵醚化剂(CHPTMA)用量等对反应效率及其产品取代度的影响。结果表明:微波干法合成阳离子淀粉,反应时间短,反应效率高;在NaOH分2次加入、NaOH与淀粉质量比为4.0%、醚化剂用量为淀粉质量的4.5%、水用量为淀粉用量的25.0%、微波功率为450 W及微波辐照时间为3.0 min等条件下,阳离子淀粉取代度为0.037 5,阳离子醚化剂反应效率高达93.76%。 相似文献
943.
《International Journal of Hydrogen Energy》2020,45(7):4490-4500
Al2O3 and MgAl2O4 supported 10% (w/w) Ni catalysts having a dispersion of 1.5 and 2.0% are active for DRM at 600 and 750 °C. High temperature reduction of both the calcined catalysts resulted in metallic Ni being formed, suggesting strong support metal interactions. The CH4 and CO2 conversion during DRM are relatively constant with time-on-stream, and are higher for Ni/MgAl2O4 than Ni/Al2O3. Carbon-whiskers are also detected on both catalysts. O2 co-feed of 2.6% (v/v) and increasing reaction temperature to 750 °C helped in decreasing the amount of carbon deposited, except for Ni/MgAl2O4 at 600 °C. Furthermore, higher conversions and H2/CO ratios are achieved. It appears that on spent Ni/MgAl2O4 a different type of carbon species was formed, and this carbon species was difficult to remove by oxygen at 600 °C. Thus, co-feeding O2, using an appropriate temperature, and choosing a suitable support can reduce the carbon present on the nickel catalysts during DRM. 相似文献
944.
为分析粘土临界坡降的影响因素,以合肥某基坑土样为例,首先开展单一粒径级土体的渗透破坏试验,分析临界坡降随干密度和均值粒径的变化规律;其次,开展多粒径混合粘性土的渗透破坏试验,讨论在干密度一定时,不均匀系数、曲率系数对临界坡降的影响。结果表明,干密度对土体临界坡降影响最为显著,均值粒径次之,临界坡降随干密度三次方的增加而线性增加,随均值粒径的增加而线性减小,随孔隙率的增大而减小;不均匀系数对土体临界坡降影响较为显著,曲率系数次之,临界坡降随不均匀系数、曲率系数的增加而线性减小。 相似文献
945.
946.
947.
Karen Trchounian Anna Poladyan Armen Trchounian 《International Journal of Hydrogen Energy》2017,42(10):6590-6597
Escherichia coli growth and H2 production were followed in the presence of heavy metal ions and their mixtures during glycerol or glucose fermentation at pH 5.5–7.5. Ni2+ (50 μM) with Fe2+ (50 μM) but not sole metals stimulated bacterial biomass during glycerol fermentation at pH 6.5. Ni2++Fe3+ (50 μM), Ni2 +Fe3++Mo6+ (20 μM) and Fe3++Mo6+ (20 μM) but not sole metals enhanced up to 3-fold H2 yield but Cu+ or Cu2+ (100 μM) inhibited it. At pH 7.5 stimulating effect on biomass was observed by Ni2++Fe2++Mo6+. H2 production was enhanced 2.7 fold particularly by Ni2++Fe3++Mo6+ at the late stationary growth phase. Whereas at pH 5.5 increased biomass was when Fe2++Mo6+ or Mo6+ were added. H2 yield was decreased compared with that at pH 6.5, but metal ions again enhanced it. During glucose fermentation at pH 6.5 biomass was increased by the mixtures of metal ions, and 1.2 fold increased H2 yield was observed. At pH 7.5 Ni2++Fe2+ increased biomass but Cu+ or Cu2+ had suppressing effect; Fe3++Mo6+ stimulated H2 production. At pH 5.5 biomass also was raised by Ni2++Fe2++Mo6+; H2 yield was increased upon Mo6+ and Mo6++Fe2+ or Mo6++Fe3+ additions. The results point out the importance of Ni2+, Fe2+, Fe3+ and Mo6+ and some of their combinations for E. coli bacterial growth and H2 production mostly during glycerol but not glucose fermentation and at acidic conditions (pH 5.5 and 6.5). They can be used for optimizing fermentation processes on glycerol, controlling bacterial biomass and developing H2 production biotechnology. 相似文献
948.
Azam Movasati Seyed Mehdi Alavi Golshan Mazloom 《International Journal of Hydrogen Energy》2017,42(26):16436-16448
The catalytic performance of Ni supported on Ce-promoted ZnAl2O4 was evaluated in methane dry reforming. The effect of different nominal loadings of cerium (3, 5 and 7 wt%) in the activity, product yield and stability was studied. Ce presented a promote effect in catalytic activity, product yield and especially in stability. However the catalytic performance was considerably influenced by the amount of cerium. SEM images presented smaller particles and TPR profiles revealed stronger active phase/support interaction by Ce addition which led to increasing methane conversion and decreasing coke deposition. Although high amount of Ce was not in favor of its promoting effect due to aggregation of CeO2 on the catalyst surface. Among the catalysts investigated, the optimal catalytic activity and stability was achieved over the sample with 5 wt% of cerium. 相似文献
949.
This paper describes some results of evaluating the influence of contact geometry on tribological characteristics. Friction characteristics obtained for a distributed contact (pin‐on‐disc and block‐on‐ring), a linear concentrated contact (pin and vee‐block and block‐on‐ring) and a point concentrated contact (ball‐on‐disc and three cylinder‐cone) are presented. The wear scars were analysed using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results show different values of friction and wear coefficients for the different types of contact geometry. The paper also assesses the effect of non‐test characteristics, e. g., vibration. 相似文献
950.
干热岩开发主要采用水力压裂的方式,而以U型井方法取代固有开发模式,具有减少水损、提高能量衰减周期,避免诱发地震等显著优势。因此,建立了U型井井筒和干热岩储层非稳态流动传热耦合模型,采用有限体积法结合Crank-Nicolson全隐式格式进行离散求解,并通过地热井数据验证了模型的可靠性。研究了干热岩开采过程中井筒及地层的温度变化特征,定量分析不同的敏感性因素对出口温度的影响,利用正交试验法明确影响取热量大小的因素排列。结果表明:各个因素的大小对出口温度影响明显,而影响取热量的因素由主到次为注入流量、水损率、岩石导热系数、水平段长度、入口温度、井筒直径。研究成果进一步完善了干热岩高效热提取理论,可为我国干热岩地热能的开发利用提供借鉴作用。 相似文献